Siemens SIMATIC IM 151/CPU, Manual

Page: 30 / 218

Addressing
2-10
ET 200S Interface Module IM 151/CPU
A5E00058783-01
In the IM 151/CPU
Data preprocessing in the DP slave:
L 2
T MB 6
L IB 0
T MB 7
Load actual value 2 and
transfer to memory byte 6.
Load input byte 0 and
transfer to memory byte 7.
Forward data to DP master
L MW 6
T PQW 136
Load memory word 6 and
transfer to peripheral output word 136
In the DP Master CPU
Postprocess received data in the DP master:
L PIB 50
T MB 60
L PIB 51
L B#16#3
+ I
T
MB 61
Load peripheral input byte 50 and
transfer to memory byte 60.
Load peripheral input byte 51 and
load byte 3;
add the values as integer data type and
transfer the result to memory byte 61.
Data preprocessing in the DP master:
L 10
+ 3
T MB 67
Load actual value 10 and
add 3,
transfer the result to memory byte 67.
Send the data (memory bytes 60 to 67) to the DP slave:
CALL SFC 15
LADDR:= W#16#12C
RECORD:= P#M60.0 Byte8
RET_VAL:=MW 22
Call system function 15:
Write the data to the output address area as of
address 300 (12C hexadecimal) with a length of 8
bytes as of memory byte 60.
In the IM 151/CPU
Receive data from the DP master (stored in MB 30 to 37):
CALL SFC 14
LADDR:= W#16#84
RET_VAL:=MW 20
RECORD:=P#M30.0 Byte8
Call system function 14:
Write the data from the input address area as of
address 132 (84 hexadecimal) with a length of 8
bytes to memory byte 30.
Postprocess received data:
L MB 30
L MB 37
+ I
T MW 100
Load memory byte 30 and
load memory byte 37;
add the values as integer data type and
transfer the result to memory byte 100.
User Data Transfer in STOP Mode
The user data in the intermediate memory is processed differently depending on
whether the DP master or the DP slave (IM 151/CPU) goes into STOP mode.
If the IM 151/CPU goes into STOP: The data in the intermediate memory
(outputs only from the slave’s viewpoint) of the IM 151/CPU are overwritten with
“0”; i.e. the DP master or a recipient in direct communication reads “0”.
If the DP master goes into STOP: The current data in the intermediate memory
of the IM 151/CPU (inputs in the slave, outputs in the master) are retained and
can be read out in the user program of the IM 151/CPU.